class Broadcaster:
"""
After retreiving media streams from a venue, the broadcaster
down-samples, transcodes, and mixes the audio into ulaw-8kHz format
recognized by other media players. It also lets you select one video
stream to forward.
"""
def __init__(self, name, app, mixAudio):
global bridge
self.flag = 1
self.app = app
self.processManager = ProcessManager()
self.log = app.GetLog()
self.selectAudio = 1
if mixAudio:
self.selectAudio = 0
# Initiate multicast address allocator.
self.multicastAddressAllocator = MulticastAddressAllocator()
self.multicastAddressAllocator.SetAllocationMethod(
MulticastAddressAllocator.RANDOM)
self.multicastAddressAllocator.SetBaseAddress(MulticastAddressAllocator.SDR_BASE_ADDRESS)
self.multicastAddressAllocator.SetAddressMask(MulticastAddressAllocator.SDR_MASK_SIZE)
# Set host and port options
self.toVideoHost = self.multicastAddressAllocator.AllocateAddress()
self.toVideoPort = 8000
self.toAudioHost = self.multicastAddressAllocator.AllocateAddress()
self.toAudioPort = 6000
self.transcoderHost = self.toAudioHost
self.transcoderPort = int(self.toAudioPort) + 2
# Register signal handling for clean shutdown of service.
signal.signal(signal.SIGINT, self.StopSignalLoop)
signal.signal(signal.SIGTERM, self.StopSignalLoop)
self.StartProcesses()
def StartSignalLoop(self):
'''
Start loop that can get interrupted from signals and
shut down service properly.
'''
self.flag = 1
while self.flag:
try:
time.sleep(0.5)
except IOError:
self.flag = 0
self.log.debug("Broadcaster.StartSignalLoop: Signal loop interrupted, exiting.")
def StopSignalLoop(self, signum, frame):
'''
Signal callback that shuts down the service cleanly.
'''
print "Exiting..."
self.flag = 0
bridge.stop()
self.tcoder.Stop()
self.StopProcesses()
def StopProcesses(self):
'''
Shutdown all processes.
'''
self.processManager.TerminateAllProcesses()
def StartProcesses(self):
'''
Start rat for audio mixing and selector for video selection.
'''
global bridge
fromVideoHost = 0
fromVideoPort = 0
fromAudioHost = 0
fromAudioPort = 0
# Create venue proxy
venueUrl = self.app.options.venueUrl
if venueUrl:
vProxy = venueProxy = VenueIW(venueUrl)
# Get stream information from venue
producerStreams = filter(lambda s: s.capability.role == "producer", vProxy.GetStreams())
for stream in producerStreams:
if stream.capability.type == "video":
fromVideoHost = stream.location.host
fromVideoPort = stream.location.port
if stream.capability.type == "audio":
fromAudioHost = stream.location.host
fromAudioPort = stream.location.port
else:
fromVideoHost = self.app.options.videoHost
fromVideoPort = int(self.app.options.videoPort)
fromAudioHost = self.app.options.audioHost
fromAudioPort = int(self.app.options.audioPort)
if debug:
print "video multicast: ", fromVideoHost, fromVideoPort
print "audio multicast: ", fromAudioHost, fromAudioPort
if fromVideoHost == 0 or fromVideoPort == 0:
if debug: print "Video stream is not received from venue, you will not receive video"
if fromAudioHost == 0 or fromAudioPort == 0:
if debug: print "Audio stream is not received from venue, you will not receive audio"
# We may receive odd ports from the venue (bug), so make
# sure rtp only uses even ports .
if fromVideoPort % 2 == 1:
fromVideoPort = fromVideoPort -1
if fromAudioPort % 2 == 1:
fromAudioPort = fromAudioPort -1
# Create commands to execute
# Start audio down-sampler (linear16 kHz -> linear8 kHz)
if debug: print "****************** START DOWN-SAMPLER", fromAudioHost, "/", fromAudioPort, " ",self.transcoderHost, "/", self.transcoderPort
self.tcoder = L16_to_L8(fromAudioHost,fromAudioPort,
self.transcoderHost,self.transcoderPort, self.selectAudio)
self.tcoder.Start()
wxapp = wxPySimpleApp()
if self.selectAudio:
audioSelectorUI = SelectorGUI("Audio Selector", self.tcoder)
if debug: print "****************** BEFORE RAT", self.toAudioPort
# Start audio transcoder (rat linear -> ulaw)
ratExec = os.path.join(os.getcwd(), 'rat')
roptions = []
roptions.append("-T")
roptions.append("%s/%d/127/l16"%(self.transcoderHost, int(self.transcoderPort)))
roptions.append("%s/%d/127/pcm"%(self.toAudioHost, int(self.toAudioPort)))
if debug: print "********* START transcoder ", ratExec, roptions, '\n'
self.processManager.StartProcess(ratExec, roptions)
self.vselector = VideoSelector(fromVideoHost, int(fromVideoPort),
self.toVideoHost, int(self.toVideoPort), 1)
self.vselector.Start()
videoSelectorUI = SelectorGUI("VideoSelector", self.vselector)
# Start video selector
if debug: print "****************** START VIDEO SELECTOR", fromVideoHost, "/", fromVideoPort, " ",self.toVideoHost, "/", self.toVideoPort
if debug: print "----------------------------------------"
if debug: print "*** Video from %s/%d is forwarded to %s/%d"%(fromVideoHost, fromVideoPort,
self.toVideoHost, self.toVideoPort)
if debug: print "*** Audio from %s/%d is forwarded to %s/%d"%(fromAudioHost, fromAudioPort,
self.toAudioHost, self.toAudioPort)
if debug: print "----------------------------------------"
# Start the bridge
print "Server URL: http://%s:%d" % (socket.gethostbyname(socket.gethostname()),9999)
bridge = Bridge(self.toAudioHost, int(self.toAudioPort),
self.toVideoHost, int(self.toVideoPort), 9999)
bridge.start()
wxapp.SetTopWindow(videoSelectorUI)
if self.selectAudio:
audioSelectorUI.Show()
videoSelectorUI.Show()
wxapp.MainLoop()
def testSetGetBaseAddress(self):
m = MulticastAddressAllocator()
# this argument is for testing, it's may not be a valid base address.
m.SetBaseAddress("127.0.0.1")
assert "127.0.0.1" == m.GetBaseAddress()